bitops: protect variables in set_mask_bits() macro
Unprotected naming of local variables within the set_mask_bits() can easily
lead to using the wrong scope.
Noticed this when "set_mask_bits(&foo->bar, 0, mask)" behaved as no-op.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 00a1a053ebe5 ("ext4: atomically set inode->i_flags in ext4_set_inode_flags()")
Cc: Theodore Ts'o <tytso@mit.edu>
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 7ddb134..d18ee0e 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -236,17 +236,17 @@ static __always_inline void __assign_bit(long nr, volatile unsigned long *addr,
#ifdef __KERNEL__
#ifndef set_mask_bits
-#define set_mask_bits(ptr, _mask, _bits) \
+#define set_mask_bits(ptr, mask, bits) \
({ \
- const typeof(*ptr) mask = (_mask), bits = (_bits); \
- typeof(*ptr) old, new; \
+ const typeof(*(ptr)) mask__ = (mask), bits__ = (bits); \
+ typeof(*(ptr)) old__, new__; \
\
do { \
- old = READ_ONCE(*ptr); \
- new = (old & ~mask) | bits; \
- } while (cmpxchg(ptr, old, new) != old); \
+ old__ = READ_ONCE(*(ptr)); \
+ new__ = (old__ & ~mask__) | bits__; \
+ } while (cmpxchg(ptr, old__, new__) != old__); \
\
- new; \
+ new__; \
})
#endif